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Description:: This paper reviews the new field of geo-measurement with metallic cable time domain reflectometry (TDR) for surveillance of transportation facilities. TDR is radar in a coaxial cable, and is especially advantageous for remote monitoring because of its inherently digital nature. Advances can be separated into those that leverage use of...
Keyword:: Structural health monitoring and Time-domain reflectometry
Creator:: Charles H. Dowding
Owner:: Nurganym Agzamova
Publisher:: Northwestern University Libraries
Language:: English
Date Uploaded:: 07/05/2017
Date Modified:: 08/14/2017
Date Created:: 2011-07-27
Resource Type:: Research Paper

Description:: Concern over construction vibration-induced cracking has led to development of a new approach to vibration monitoring called autonomous crack measurement (ACM) and illustrated in Figure 1. This paper describes the concept as well as sensor performance in the first test house fitted an ACM system. Response of three cracks in...
Keyword:: concrete masonry unit
Creator:: Charles H. Dowding and Michael Louis
Owner:: Chris Diaz
Date Uploaded:: 08/14/2017
Date Modified:: 08/14/2017
Date Created:: 2003
Resource Type:: Article

Description:: This paper summarizes micro-inch response of cosmetic cracks in a typical slab-ongrade ranch style house to both construction equipment-induced vibration and environmental (weather) effects. This structure was instrumented, and its response studied as part of the development of an Autonomous Crack Measurement (ACM) system. ACM systems are intended to record...
Keyword:: Autonomous Crack Measurement
Creator:: Charles H. Dowding and Mickey L. Snider
Owner:: Chris Diaz
Publisher:: American Society of Civil Engineers
Date Uploaded:: 08/14/2017
Date Modified:: 08/14/2017
Date Created:: 2004
Resource Type:: Part of Book

Description:: Cracking is one of the most common concerns cited by owners of structures adjacent to construction or mining blasting. While a large database of case studies documenting the relative insignificance of ground motion induced by responsible blasting compared to weather effects on cracks in nearby structures has been established, the...
Keyword:: Autonomous Crack Measurement
Creator:: Charles H. Dowding and Jeffrey E. Meissner
Owner:: Chris Diaz
Date Uploaded:: 08/14/2017
Date Modified:: 08/14/2017
Date Created:: 2011
Resource Type:: Research Paper

Description:: This presentation is intended to provide background on the principles involved in geotechnical and infrastructure applications of Time Domain Reflectometry (TDR). TDR is basically radar in which a voltage pulse is launched along a coaxial cable. A reflection of the voltage pulse occurs at every location where the cable is...
Keyword:: Time-domain reflectometry and Structural health monitoring
Creator:: Charles H. Dowding and Kevin M. O'Connor
Owner:: Nurganym Agzamova
Publisher:: Northwestern University Library
Language:: English
Date Uploaded:: 07/05/2017
Date Modified:: 08/14/2017
Date Created:: 2000
Resource Type:: Report

Description:: Two longwall coalmine panels were mined at a depth of approximately 156 m (510 ft) beneath I-70 east of Washington, Pennsylvania such that it crossed the width of one panel at two locations. The Pennsylvania Department of Transportation (PennDoT) assumed responsibility for real time monitoring of both ground deformation and...
Keyword:: Structural health monitoring
Creator:: Charles H. Dowding, Kevin M. O'Connor, David J. Whitlatch , and Ronald J. Clark
Owner:: Nurganym Agzamova
Publisher:: Northwestern University Libraries
Language:: English
Date Uploaded:: 07/05/2017
Date Modified:: 08/14/2017
Date Created:: 2001
Resource Type:: Report

Description:: This appendix synthesizes micrometer changes in crack width in response to both long term (environmental) and transient (blast vibration) of four of the structures in the main body. The appendix begins with a description of the genesis of the study and instruments employed. Response of the distressed wood-framed structure in...
Keyword:: Structural health monitoring
Creator:: Charles H. Dowding and Laureen M. McKenna
Owner:: Nurganym Agzamova
Publisher:: Northwestern University Libraries
Language:: English
Date Uploaded:: 07/05/2017
Date Modified:: 08/14/2017
Date Created:: 2003
Resource Type:: Other

Description:: Cosmetic and structural cracks are a large concern for homeowners. Although these cracks can develop from a variety of causes: differential foundation settlement, occupant activity, climatological effects, as well as dynamic events, people tend to look to dynamic events like blasting, construction, or traffic vibrations to be the culprit. This...
Keyword:: Crack responses , Structural integrity assessment , and Ground motions
Creator:: Jeffrey Meissner and Charles H. Dowding
Owner:: Nurganym Agzamova
Publisher:: Northwestern University Libraries
Language:: English
Date Uploaded:: 07/05/2017
Date Modified:: 08/14/2017
Date Created:: 2009
Resource Type:: Report

Description:: The notion of blasting, even in a controlled setting such as a limestone quarry, can be alarming to residents and business owners within earshot. Because humans are inherently sensitive to blast-induced vibrations, they perceive that the structures in which they live in are equally sensitive. The goal of this project...
Keyword:: Ground motion, Concrete block structure, and Structural health monitoring
Creator:: Charles H. Dowding and Jeffrey E. Meissner
Owner:: Nurganym Agzamova
Publisher:: Northwestern University Libraries
Language:: English
Date Uploaded:: 07/05/2017
Date Modified:: 08/14/2017
Date Created:: 2009
Resource Type:: Report

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